Fix for bug 5468, support CSS3 :only-child and :only-of-type selectors.

        Reviewed by olliej

        Added fast/css/only-child-pseudo-class.html, fast/css/only-of-type-pseudo-class.html

        * css/CSSSelector.cpp:
        (WebCore::CSSSelector::extractPseudoType):
        * css/CSSSelector.h:
        (WebCore::CSSSelector::):
        * css/CSSStyleSelector.cpp:
        (WebCore::CSSStyleSelector::checkOneSelector):

LayoutTests:

        Add test for bug 5468, supporting :only-child and :only-of-type in CSS3.

        Reviewed by olliej

        * platform/mac/fast/css/only-child-pseudo-class-expected.checksum: Added.
        * platform/mac/fast/css/only-child-pseudo-class-expected.png: Added.
        * platform/mac/fast/css/only-child-pseudo-class-expected.txt: Added.
        * platform/mac/fast/css/only-of-type-pseudo-class-expected.checksum: Added.
        * platform/mac/fast/css/only-of-type-pseudo-class-expected.png: Added.
        * platform/mac/fast/css/only-of-type-pseudo-class-expected.txt: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@29944 268f45cc-cd09-0410-ab3c-d52691b4dbfc